Supervisory signaling in telephone or like switching systems



M. E. MALoNl-:Y 2,468,299 SUPERVISORY SIGNALING IN TELEPHONE OR LIKE SWITCHING SYSTEMS I 3 Sheets-Sheet 1 April 26, 1949.

Filed July 7, 1945 NIE .Eg ww /N V/vron M. E.' MALONE'Y sy A TTORNE )f x. murio, UF*

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MALONEY' 1N TELEPHONE April 26, 1949. M E.

l sUPERvIsoRY SIGNALING 0R LIKE SWITCHING SYSTEMS 3 Sheets-Sheet 2 n. .lll u.

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Filed July '7, 1945 La. in.

/NVENTOR By M MALVoA/Ey CML Amm/5v April 26, 1949. M. E. MALONEY 2,468,299 SUPERVISORY SIGNALING IN TELEPHONE Y OR LIKE SWITCHING SYSTEMS Filed July 7, 1945 3 shams-smet' 5 POLAR! A REG/Sm? SEND/:R Rs2 POL ARI ZE ATTORNEY atented- Apr. 26, 1949 SUPERVISQRYi SIGNALING :,IN .TELEPHONE COR, LIKE SVITCHNG *SYSTEMS Martin -'E.-Ma1oney, Flush-ing, `N.'Y., assigner to Bell Telephone Laboratories, Incorporated; New YorkfN. a corporation of .New York Application'July 7, 1945, VvSerial No.l 603;(584

vl-olaims. y1

This invention relates to signaling systems and particularly to signaling-adapted for use-in au- 1 tornatic4 telephones-systems.

nals ffor obtaining the-desired control inwsuch systems.

InY automatic telephone systems yof the Amarker Acontrolled'typejit issknown to firstftest the-'di- `-recttrunks over which iacall-may `loey completed 4andifall of the direct'trunks'arebusy to test thetrunks -in Van alternate --route group. The` al tornate routi-ngof tol-loalls isf-more complex than f the alternate-routing of'loca1-cal-1sthroughl tandemolices-loecausey to'll connections may lie-built 'up rt-hroug'ha plurali-ty of intermediate 4switching "points Y and loecause 4of the multiplicity `of I'routes whichmay Vhe Jused to reach the terminatming* toll office. Inmarnlal-toll systems,f.the-choice -of alternate l routes -is under Lthe controlfof `the originatingtoll operator @because i a callli-s usually --returned to the `originating `operator ...when a ltrur-iks busy condition is encountered. In :dial

systems, 1the- Cost-and complexity of hreturning calls to the/originatingpoint'make it. desirable Valways-to proceedas-fiar as possible along the route 'originallyvchosen '/When a marker in a toll` ofce Aa ridsall trunks r toato'll office. lBl busy, 2 the call is extended .over a trunk toxanzalternate '.toll oflice'C. Ifat thatmtime, there'isran idle trunk from ofcefCtooioe B the. callis 4completed thereover; butrifzthere isanoiidle trunk -from ofce C to oice Bfthefmarker in..of1ice:C

Arnayiether:try itsnalternate routetofoflicesB or send back :anoverflow rsignal. A,:second,alter nate route `may .lead :tona: third or, worse, the.a1 ternate route :from oiiice C to ofcetBmaybe '.throughfoice A; and-.both of such conditions `are objectionable. If an overflows/signalloe given vand, the originating operator Waits` for-the overf-tlow signal tol change' tothe recorder signal-.when an .idle :trunk -becomesavalable at oflcefC,

Atrunks directly-'from :office 'Alito oice B maya-bef-comeavailablewithout,thezoperatorlknowingthat :,thisis so.

"A way f .of circumventing `these* diiiiculties is to ite'llfthef alternate'- route,- o'ice` C:that the incom- I.ingacall is auf:alternateroutev call land;y if' the call cannot?rbefurtheroextended overa; regular route 2 to ofce B,that a'reorder signal befgiven'toofnce A. The register -senderat koffice v`A recognizes the reorder Asignal Vas Y'an alternate route al1- itrunks-busy `signal, `drops the connection-to fofk5 ceCyca'lls'ior afnewmarker and asks-forjthe original route toeceB-and alsotellshthene'w marker lnot to Ktry the alternate rou-te. -method prevents 4alternate --routing back -to e the v o-fiicein which an alternateroutewas first-chosen and gives'y the overflowl signalifrom thelast'nor- -mal route oice inthe-connection.

A feature `of lthey `invention is the provision -of means in 1an automatic Ytoll -oice comprising sender-marker controlled Y switohesiorJ transmitt-ing over a selectedtrunk-a-partioularisignallif 4-tl'-1e call isbeing-routed `over-a:trunk: in the normal-route group 'and' a "different signal -i-fthecall is being routed over a trunk in the alternateroute group.

Another feature of the invention isl the provision-of means in an automatic toll 'oice 4corn-prising sender-marker controlled switches forextending yan-incoming call `either through a-trunk in the normal route group orthrougha--trunkin f the `alternate route-group` if `the oice is -the Vnormal route for 'completing the-oall=frornl the `preceding office -and for extending -a call -only through a -trunkin the-normal route groupl iff-the oi-Elco isthe alternate lroute 1`for'coX-mzrletingd the 130 -call frornthe preceding oijce.

A:Another feature or theinvention isfthe provision of -rneans in -an automatic vtoll oiiioe-corn- -prising sender-marker controlled 4-sWitches for lextending Athe-'call Yonly -through a trunk'inthe f normal route group if the'orlfcef is the alternate l in thedrawings vlout v-is generally applicable --to automatic-` telephone systems: in -which f `common .control means is provided for control-ling theop- -eration ofv switches, of Mwhatever @ty-pe, hthrough @which desiredconnections. are established.

e'Referringftofdrawing:

Fig. 1 shows a toll oce A comprising an outward or originating toll operators position I and cord II, a jack ended trunk circuit Tl, incoming and outgoing link switches of the cross bar type, outgoing trunks OTI and 0T2 and common control equipment including the register-sender RS! and marker M; and

Figs. 2 and 3 show another toll oce B comprising an incoming trunk circuit ITZ, incoming and outgoing link switches of the cross bar type, outgoing trunks GT3 and GT4, a reorder trunk circuit T5, and common control equipment including the marker M2 and register-sender RSZ.

The toll operator position i0 includes a key set of the type which transmits alternating current signals, each of which consists of current of a different two out of six frequencies. Reference may be had to the patent application Serial No. 550,070, filed August 18, 1944, by B. McKim and O. Myers, U. S. Patent No. 2,382,893, granted August 14, 1945, for disclosure of a system in which an operators position includes a key set for transmitting such signals. The cross bar switches, register-sender RS! and marker Ml are generally similar to those disclosed in detail in the patents to Carpenter 2,089,921 -granted August 10, 1937,

and 2,093,117 granted September 14, 1937, and in the patent to G. V. King et al. 2,236,246 granted March 25, 1941. Reference may be had to the aforementioned application of B. McKim and O. Myers for disclosure of a register-sender arranged to receive and register alternating current twofrequency signals and arranged to transmit like signals over the selected outgoing trunk. The register-sender RS! differs from the sender of the McKim-Myers patent only in that it is arranged to transmit two different gate or KP signals, one in case the selected trunk is in the normal route group and the other in case the selected trunk is in the alternate route group. The marker MI is similar to the marker of the aforementioned King et al. patent except that the alternate route relay, which is operated when all of the trunks in the normal route group are busy, includes a contact for operating the relay in the register-sender `which controls the KP signals which are transmitted over a selected trunk.

The incoming trunk circuit 1'12, switches, register-sender RSZ and marker M2 are similar to the corresponding circuits disclosed in the aforementioned McKim-Myers application and King et al. patent except that the alternating current key pulsing receiving circuit of the register-sender RSZ is arranged to receive either one of two different KP signals, one of which indicates the call is being extended over a trunk in a normal route group and the other of which indicates the call is being extended over a trunk in the alternate route group from the preceding office. The marker M2 differs from the markers disclosed in the McKim-Myers application and King et al. patent in that it includes a relay which is operated when the call being handled is an alternate route call to prevent the marker from testing trunks in the alternate route group if all of the outgoing trunks in the normal route group are busy.

Assume now that the toll operator at position I0 has answered a call from a local subscriber and is extending the call through cord Il, jack I2 and trunk circuit Tl'. An idle register-sender is thereupon attached to the trunk TI and a sender v attached signal is transmitted to the operator position; whereupon the operator actuates the KP key to send a signal to prepare the registersender RSI for receipt of oice code and numercal digit signals which are transmitted by operation of the operators key set through the cord, jack and trunk Ti, over conductors i3 to the register-sender RSL The key pulsing signals are received and reg' tered in the sender RSI; and a marker Mi is attached to the sender in usual manner when the office code digits have been received. The marker M thereupon receives the toll code digits from the register-sender and translates these digits to effect the operation of a route relay 2l. The marker Ml then tests the trunks in the normal route group and routes the call over an idle trunk, for instance, the trunk circuit OTS, by controlling the operation of the incoming and outgoing switches. Ii all of the trunks in the normal route group are busy, the route relay 2l is released and the alternate route relay 28 is operated; and the marker then tests the trunks in the alternate route group and routes the call over an idle trunk, for instance, the trunk circuit 0T2, by controlling the operation of the district and office switches. The operation of the route relay 2l or the alternate route relay 28 eifects the transmission to the registersender of information needed to complete disposition of the call.

Assume further that the call is one routed through a plurality of toll offices and that the selected outgoing trunk circuit is arranged for alternating current pulsing to the next office. When the call is extended to the outgoing trunk circuit, a connect signal is transmitted over the associated toll line to the distant cnice to effect the connection of the associated incoming trunk circuit to a register-sender. When a sender-attached signal is transmitted back over the toll line to the outgoing trunk circuit, the register-sender in the originating toll oce, transmits a KP signal to prepare the register-sender in the next oice for the receipt of toll and local cnice code and numerical signals. Only so much of the register-sender is shown as is necessary for the transmission of the required KP signal. Relays 2l and 22 correspond to relays 3406 and 2910 respectively of the aforementioned McKim-Myers application. If the route relay 2l controls the selection of an outgoing trunk circuit, relay 24 of the register-sender remains normal and the KP signal transmitted consists of an impulse of alternating current of frequencies 1100 cycles per second and 1700 cycles per second. The circuit path for effecting this transmission is traced from the secondary winding of tone source transformer 25, through back contacts of relays 2li and 22, front contacts of relay 2i, transformer 20, conductors i9, the selected channel through the incoming and outgoing switches and the outgoing trunk circuit OTl' to the toll line TLI. If, however, the alternate route relay 23 controls the selection of an outgoing trunk circuit, relay 24 of the register-sender is operated. Relay 2li locks until the sender is released, and with relay 24 operated, the KP signal transmitted consists of an impulse of alternating current of frequencies 1300 cycles per second and 1700 cycles per second. The circuit path for effecting this transmission is traced from the secondary winding of transformer 2li, through front contacts of relay 24, thence to the outgoing trunk circuit 0T2 and toll line T112. In either case, when the KP signal has been transmitted, relay 22 is operated to connect the outgoing pulsing control relays through conductors 23 to the selected outgoing trunk circuit, thereby to effect the transmission of the signals representing the toll and local oiiice codes and nurmerieal'digits registered-in the register-sender 'in-the `manner described in detail in the `aiforementionedJMcKim-Myers application.

liReferring now to the oiiice B shown in Figs. 'ZETHar-id, the receipt'of a connect signal by in- =coming trunk circuit IT2 over the associated toll "lineffrom a preceding'toll oce effects the conniection of an idle 'register-sender RSZ to the `-vtrunkfcircuin and a `sender-attached signal is transmittedfrom this sender over the toll line tto *thea-preceding oiiice. The register-sender is arranged to receive alternating current signals, tl'ie'first-signal being a KP signal. The signal -impulsereceiving circuit shown in Fig. 3 is simi- 4-lar tothatdisclosedin Fig. 32 of the aforementionedeMcKim-Myers application but is modied torselectivelyrespond to a KP signal consisting y-ofecurrent of l:frequencies 1100 and 1700 cycles "persecond and a KP signal consisting of current offrequencies 1300 and 1700 cycles per secon'd,'the `particular combination of frequencies making-up the KP signal depending on whether ^oIiiceB is in the regular route or in the alternate "route'for the call in question. Assume iirst that the normal route KP signal is received. The

*46,*and effects the operation of relay 56. With `^b'oth ofrelays 53 and 56 operated, conductor 60 is disconnected from ground thereby deenergizing the normally energized lower windings of polar- "ize'd relays 6l and 10. `With the lower winding ofyrelay' 6I deenergized, the energization of the Vupperwinding becomes effective to open the right contact and close the left contact of this relay, this `action being delayed for about .048 second by ,the charging of condenser 64. As soon after irrelay 6l is operated as either of relays 53 or 56 'releases ground is again connected to conduc- 'tor' 60, `thence through the left contact of relay 61 and windings of both of relays 62 and 63 to "batterythereby causing the operation of both ofrelays 62 and 63. The operations of relays 62 and 63connect the front contacts of the signal "receiving relays 5I, 52, 53, 54, 55 and 56 to conf'ductors A, B, C, D, E and F which are connected "to the registerv relays `which register the code and fnumerical digits. isnot4 affected when the KP signal received con- "sists of 1100and 1700 cycles per second since `neither of its windings will be energized when l'ground is disconnected from conductor 60 as above described. The call is thereafter completed l'underthe `control ofan associated marker M2 finusual manner. If an idle trunk is available in thefgroup identified by the operated normal route lre1ay,`such as route relay 8|, the call will prolceedover the normal route; but if all of these trunks' are busy, the alternate route relay will be Vfoperated to effect extension of the call over a 'trunk in the alternate route group.

`y'Assume next that the incoming call is extendled to trunk circuit ITI of office B as an alternate l"route, in which case the KP signal received will consist ofirequeneies 1300 and 1700 cycles per rsecond. 'The current of 1300 cycles'per second jpasses through iilter 34 to energize tube 44 and `operate-relay 54; and the current of 1700 cycles fper second passes through lter 36 to energize "tubef46 and operate relay 5E. With both of w'relays`54 and 56- operated, ground is disconnect- "edi-'from-'conductor l60` to lcause the deenergiza- "=l ion of the -lower windings of relays '6| and l'IIJ It is to be noted that relay and'relayl is operated-tdopenfV its right contact and close its left contact, thesame as for-the normal route KP-signal. However, since relay 54 is operated, a circuit' path is closedfor maintaining the energization of the-upper Winding of relay '10; ythis circuit path is traced from the upper winding `of -relay v'10, `through a back contact of relay 62,'leftz contact of rel-ay 54, another back-contact of relayt62, -and right contact of relay `53 to ground. Relay 'IIJ is thus operated to close its'left contact; and when relays`62 and 63 are operated by the closing of the left Contact of relay 60?, relay 10 is locked through its upper winding in series with-the winding of relay 1|. The lower winding of relay '10 cannot again be energized while relay'62 is operated. When a marker M2 is associated with the register sender RSZ, ground is connected to conductor 12 to operate relay in the marker, thereby to indicate to the marker that the call is not to be routed through an alternate route in case all of the trunks in thenormal route are busy. Consequently, when all normal route trunks are busy, the reorder route relay 83 is operated, a reorder trunk is selected and a reorder signal is transmitted to the preceding office.

What is claimed is:

l. In a trunlring and signaling system, two groups of trunk linesfmeans for eiectingthe selection of an idle line in one of said groups, means for effecting the selection of an idle line in the other of said groups in case all of the lines in said one group are busy, means for transmitting a signal of one character over the selected line if in said one group and a signal of a difierent character over the selected line if in said other group, and means for transmitting selective signals over the selected line following said signal ofthe one character or the other, the selective signals then transmitted being the same if the selected line is in said one group as ir" the selected line is in said other group.

2. In a signaling system, a line, signal-receiving means responsive to a plurality of different selective signals incoming over said line, certain of said signals being letter or numerical digit signals and other signals being gate signals one oi which precedes the first digit signal, only, of each train of letter or numerical digitl signals, means for registering the letter code or-numerical digit signals received, and means responsive to any one of 4said different gate signals for enabling the operation of said registering means.

3. In a signaling system, a line, signal receiving means responsive to a-plura'lity of different selective signals incoming over said line, eachdifferent signal consisting of an'impulse of alternating current of a `different combination of two frequencies, certain of said signals being letter or numerical digit signals and other signals'being gate signals one of which precedes the rst digit signal, only, of each train of letter or` numerical digit signals, and means responsiveto any one of said different gate signals for enabling the operation of said registeringrneans.

4. In a trunking and signaling system, an incoming-trunk circuit, groups Vof outgoing trunk circuit, a-register-sender connected to said trunk circuit and comprising signal receiving means responsive to a plurality of'diiierent signals, each of certain of said signals constituting a preparatory signal and other'of'sai'd signals constituting office code and numericalV digit signals, said register-sender further -comprisingregisters settable responsive to said o'cecode" and numerical Jdigit signals, means responsive to any of said different preparatory signals for enabling the setting of said registers, means comprising a marker controlled in accordance with the setting of oflice code registers for determining the route of the call and for connecting said incoming trunk circuit to an idle outgoing trunk circuit in the normal route group or to an idle outgoing trunk circuit in an alternate route group in case all of the trunks in the normal route group are busy, and means rendered eiiective in case the preparatory signal received to enable the setting of the registers is a particular signal for preventing the connection oi the incoming trunk circuit to a trunk in the alternate route group.

5. In a trunking and signaling system, an incoming trunk circuit, groups of outgoing trunk circuits, a register-sender connected to said trunk circuit and comprising signal receiving means responsive to a plurality ci different signals, each diierent signal consisting of an alternating current impulse or a different combination of two freqnencies, each of certain of said signals constitsting a preparatory signal and others of said signals constituting cnice code and numerical digit signals, said register-sender further comprising registers settable responsive to said oliice code and numerical digit signals, means responsive to any of said different preparatory signals for enabling the setting of said registers, means comprising a marker controlled in accordance with the setting of the office code registers for determining the route of the call and for connecting said incoming trunk circuit to an idle outgoing trunk circuit in the normal route group or to an idle outgoing trunk circuit in an alternate route group in case all of the trunks in the normal route group are busy, and means rendered effective in case the preparatory signal received to enable the setting of the registers is a particular signal for preventing the connection of the incoming trunk circuit to a trunk in the alternate route group.

6. In a trunking and signaling system, a first office comprising a register-sender, a plurality of groups of outgoing trunks and a marker, said marker having means controlled in accordance with the setting of registers in the register-sender for affecting the selection of a trunk in the normal route group and for effecting the selection of a trunk in the alternate route group in case all of the trunks in the normal route group are busy, means in the register-sender of the first ofce for transmitting a preparatory signal of one character through the selected trunk if in the normal route group and of a different character if in the alternate route group, means in the register-sender for transmitting oiiice code and numerical digit signals through the selected trunk following the preparatory signal, a second oflice terrninating the trunks in said normal route group, a, third oiiice terminating the trunks in said alternate route group, each of said second and third omces comprising incoming trunk circuits, outgoing trunk circuits, register-senders, markers and switches, means eiective in response to seizure in said rst cnice of an outgoing trunk circuit in said normal route group for connecting an idle register-sender with the associated incoming trunk circuit in said second ofce, means effective in response to seizure in said rst oice of an outgoing trunk in said alternate route group for connecting an idle reg- 'istersender with the associated incoming trunk circuit in said third oce, means in the register- 8. senders of said second and third offices for responding to either type of preparatory signal and to oice code and numerical digit signals to register the oce code and numerical digits, means comprising a register-sender in said second olice connected to an incoming trunk circuit associated with an outgoing trunk circuit in the normal route group of said iirst office and comprising a marker in said second ofce for connecting said incoming trunk circuit to an outgoing trunk circuit in a normal route group outgoing from the second office or to an outgoing trunk circuit in an alternate route group outgoing from the second oice if all of the trunk circuits in the normal route group are busy, and means comprising a register-sender in said third oice connected to Ian incoming trunk circuit associated with an outgoing trunk circuit m an alternate route group of said rst oice and comprising a marker in said third office for connecting said incoming trunk circuit to an outgoing trunk circuit in a normal route group outgoing from said third ofce but not t0 an outgoing trunk circuit in the alternate route group outgoing from said third oice.

'7. In a trunking Iand signaling system, a iirst oliice comprising a register-Sender, a plurality of groups of outgoing trunks and a marker, said marker having means controlled in accordance with the setting of registers in the register-sender for eecting the selection of a trunk in the normal route group and for effecting the selection of a trunk in the alternate route group in case all of the trunks in the normal route group are busy, means in the register-sender of the iirst omce for transmitting a preparatory signal of one character through the selected trunk if in the normal route group and of a different character if in the alternate route group, means in the register-sender for transmitting office code and numerical digit signals through the selected trunk following the preparatory signal, a second oiiice terminating the trunks in said normal route group, a third oiiice terminating the trunks in said alternate route group, each of said second and third oflices comprising incoming trunk circuits, outgoing trunk circuits, register-senders, markers and switches, means eiective in response to seizure of an outgoing trunk circuit in said normal route group for connecting an idle register-sender with the associated incoming trunk circuit in said second oihce, means eective in response to seizure of an outgoing trunk in said alternate route group for connecting an idle register-sender with the associated incoming trunk circuit in said third omce, means in the register-senders of said second and third ofces for responding to either type of preparatory signal and to of-ce code and numerical digit signals to register the oiiice code and numerical digit, means comprising a register-sender in said second omce connected to an incoming trunk circuit associated with an outgoing trunk circuit in the normal route group of said rst oilice and comprising a marker in said second office for connecting said incoming trunk circuit to an outgoing trunk circuit in a normal route group outgoing irom said second office or to an outgoing trunk circuit in an alternate route group outgoing from said second oice if all of the trunk circuits in the normal route group are busy, and means comprising a register-sender in said third oiice connected to an incoming trunk circuit associated with an outgoing trunk circuit in analternate route group of said rst oftice and com- `prsing a marker in said third ofiice for connecting s-aid incoming trunk circuit to an outgoing trunk circuit in a normal route group outgoing from said third ofce or to a reorder circuit for transmitting a reorder signal to said first office, but not to an outgoing trunk circuit in the alternate route group outgoing from said third ofce.

MARTIN E. MALONEY.

REFERENCES CITED The following references are of record in the file of this patent:

Number UNITED STATES PATENTS Name Date Williams Dec. 7, 1926 Radke Mar. 31, 19'31 Hersey Nov. 4, 1941 Keyser Dec. 9, 1941 Taylor Nov. 17, 1942 Gillings Aug. 28, 19451 

